Ascenso, José R.

Avelino, Helena M. N. T.

Caetano, Fernando J. P.

Fareleira, João M. N. A.

Sequeira, Maria C. M.

English

Diffusion Fundamentals (E-Journal)

Self-diffusivity of a homologous series of ethylene glycols: Experimental measurements, relation with viscosity, correlation and prediction methods José R. Ascenso1, Maria C. M. Sequeira1, Helena M. N. T. Avelino1,2, Fernando J. P. Caetano1,3*, João M. N. A. Fareleira1 1Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal 2Área Departamental de Engenharia Química, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Lisboa, Portugal 3Departamento de Ciências e Tecnologia, Universidade Aberta, Lisboa, Portugal *fernando.caetano@uab.ptThis work reports the self-diffusivity measurements of liquid diethylene, triethylene and tetraethylene glycols from 293 K to 343 K by the PGSE-NMR technique. The dependence of the diffusion coefficients with both the temperature and the molecular mass of the oligomers for the interpretation of their local structure was studied. The diffusivity results are interpreted by means of a Stokes-Einstein-Sutherland-type equation. The hydrodynamic radius, obtained directly from the self-diffusion coefficients, is compared with the van der Waals and the hard sphere radii [1]. The viscosity and density data needed for the radii calculation were recently published by this group [2]. This study is part of a programme of measurements of thermophysical properties, namely, viscosity, self-diffusivity and density, aiming to study the correlation of the transport properties of ethylene glycols [3]. Ultimately the work will involve the prediction of thermophysical properties of liquid PEGs. References [1] R. Ascenso, G. Rubiom, J. C. F. Diogo, H. M. N. T. Avelino, F. J. P. Caetano, J. M. N. A. Fareleira: Self-diffusivity measurements of dimethyl, diethyl, dipropyl, dibutyl, bis(2-ethylhexyl) adipates from (293–339) K by a PGSE–NMR spin-echo technique. Fluid Phase Equilib. 410, 26-32 (2016). [2] M. F. V. Pereira, H. M. N. T. Avelino, F. J. P. Caetano, J. M. N. A. Fareleira: Viscosity of liquid diethylene, triethylene and tetraethylene glycols at moderately high pressures using a vibrating wire instrument. Fluid Phase Equilibria 480, 87-97 (2019). [3] H. M. N. T. Avelino, J. C. F. Diogo, F. J. P. Caetano, J. M. N. A. Fareleira: Viscosity and self-diffusion coefficients of dialkyl adipates: A correlation scheme with predictive capabilities. J. Chem. Eng. Data 60, 3696–3702 (2015). This work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/1

Self-diffusivity of a homologous series of ethylene glycols: Experimental measurements, relation with viscosity, correlation and prediction methods

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Self-diffusivity of a homologous series of ethylene glycols: Experimental measurements, relation with viscosity, correlation and prediction methods

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Diffusion Fundamentals (E-Journal)